| Title | Submitted by |
|---|---|
| ÆGIS — An Astrophysics Experiment for Grating and Imaging Spectroscopy [PDF] | Bautz, Marshall |
| AXSIO — The Advanced X-ray Spectroscopic Imaging Observatory [PDF] | Bookbinder, Jay |
| Development of Fast Readout Technology in Support of Future X-Ray Astronomy Missions [PDF] | Burrows, David |
| The WHIMEx Mission Concept and Lessons Learned [PDF] | Cash, Webster |
| Three Meter Capacity Diamond Turning Machine For X-Ray Telescope Components [PDF] | Casstevens, John |
| Precision-Deployable, Stable, Optical Benches for Cost-Effective Space Telescopes [PDF] | Danner, Rolf |
| REDUX: A Flexible Path for X-ray Astronomy [PDF] | Elvis, Martin |
| EPE: The Extreme Physics Explorer [PDF] | Garcia, Michael |
| A Hard X-Ray Telescope for an X-Ray Spectroscopy Mission, Extending the Bandwidth [PDF] | Gorenstein, Paul |
| Epoch of Reionization Energetic X-ray Survey (EREXS) [PDF] | Grindlay, Jonathan |
| The High Energy X-ray Probe (HEX-P) [PDF] | Harrison, Fiona |
| Critical-Angle Transmission Gratings for High Resolution, Large Area Soft X-ray Spectroscopy [PDF] | Heilmann, Ralf |
| Enabling Technologies for the High Resolution Imaging Spectrometer of the Next NASA X-ray Astronomy Mission: Options, Status, and Roadmap [PDF] | Kilbourne, Caroline |
| Xenia: A Probe of Cosmic Chemical Evolution [PDF] | Kouveliotou, Chryssa |
| The Black Hole Evolution and Space Time (BEST) Observatory [PDF] | Krawczynski, Henric |
| The Warm-Hot Intergalactic Medium Explorer (WHIMex) [PDF] | Lillie, Charles |
| Soft X-ray Polarimetry [PDF] | Marshall, Herman |
| Reflection Grating Spectrometers [PDF] | McEntaffer, Randall |
| Space Communication Rates at Multi-GBPS [PDF] | McIntyre, Todd |
| Wide Field X-Ray Telescope Mission [PDF] | Murray, Stephen |
| Active Pixel X-ray Sensor Technology Development for SMART-X Focal Plane [PDF] | Murray, Stephen |
| SAHARA: Spectral Analysis with High Angular Resolution Astronomy [PDF] | Mushotzky, Richard |
| Improving X-Ray Optics Through Differential Deposition [PDF] | Ramsey, Brian |
| Super Mon & Black Hole Tracker [PDF] | Rao, A.R. |
| The Advanced X-ray Timing Array (AXTAR) [PDF] | Ray, Paul |
| 5-Stage Continuous ADR for Future X-Ray Missions [PDF] | Shirron, Peter |
| Concept for an orbiting wide field X-ray imaging spectrometer (WFXIS) [PDF] | Ullmer, Melvin |
| Improving the performance of X-ray optics with magnetostrictive films [PDF] | Ullmer, Melvin |
| SMART-X, Square Meter, Arcsecond Resolution X-ray Telescope [PDF] | Vikhlinin, Alexey |
| Next Generation X-ray Optics: High-resolution, Light-weight, and Low-cost [PDF] | Zhang, William |
| Questions |
|---|
| What is the redshift distribution of the 100 targets selected to study the WHIM and how do these studies complement or extend those of the Lyman alpha forest and BOSS? |
| AEGIS will be very effective at studying galactic black holes. How will new black hole transients be found and how will transitions in state be identified in galactic sources? |
| Questions |
|---|
| How much longer exposures are needed to do SMBH spin measurements, since there is no area >10keV? |
| How much longer exposures are needed to do SMBH spin measurements, since there is no area >10keV?How do you identify the 100 stellar mass black holes for spin measurement? |
| With its small FOV, how will the target list for high-z AGN be determined to gain spin measurements beyond the local universe? |
| What is the observing program for clusters (rastering, exposure time, etc.)? Please give more detail. |
| How much more expensive would a 5“ mirror be? |
| Questions |
|---|
| Can AXTAR address “What happens close to a black hole” using Fe-L line measurements? |
| Given the MSFC ACO detailed studies, what is to be gained by a GSFC MDL run? |
| Questions |
|---|
| One might conclude from Figure 1 that the test of strong gravity comes mainly from the variation of polarization angle with energy in the 2-10 keV band. Is this inference correct? It would be helpful to know what specific science the hard-band (E>10 keV) polarimetery enables that could not be done in the soft-band alone. |
| Can you explain in detail how you get out to z=6? |
| The quoted AGN counts (380 in 12x12' with 10" HPD) seem to ignore confusion issues. If these are accounted for, does the expected redshift distribution (Fig 2) change much? |
| Can you add some detail on the cluster science? |
| What is the expected polarization signal of an LMXB in outburst and how will BEST be able to “tighten the emission locale constraints?” |
| How is your science affected if the mirrors can only achieve 30” angular resolution? |
| The RFI states that the HPD diameter of the mirrors is 10” at 4.5 keV. How does the HPD vary from 4.5 keV to 70 keV? |
| Is 7% MDP enough to do IXO science, which had 1% MDP? (page 3, table 1), and how does this relate to the 1% MDP in the science matrix (page 2)? |
| Please provide the effective area curves for the TPC and high-energy polarimeter. The RFI states that the TPC has 99% detection efficiency at 2 keV and 10% at 8 keV. No numbers are provided for the high-energy polarimeter. |
| Questions |
|---|
| How will the much higher collecting area of EPE compensate for reduced spectral resolution specifically for WHIM measurements? |
| How well do measurements on arc minute scales of turbulent velocities in clusters of galaxies constrain models? |
| With the limited angular resolution, how can it be determined if measurements of gas turbulence in clusters are due to AGN outbursts rather than to mergers? |
| It isn’t clear how observations of bursting neutron stars are carried out. Is the idea to stare at a burster with a high burst rate, or to trigger an observation with some other indication of bursting activity? |
| Over what range of redshift will the metal enrichment measurements be made? Over what redshift range are measurements required to determine when and how the metals are produced? |
| Since the beam fills the detector field of view, how would instrument background be determined? |
| 2.5 eV resolution corresponds to delta v of 117 km/s at 6.4 keV. How can the instrument resolve 100 km/s gas velocities (p. 6)? |
| Do the effective area curves account for the fraction of the collecting area that actually falls on the detector plane? |
| What is the operational status of the “code division multiplexing” technique? |
| What is the distribution of energy resolution on the existing 32x32 pixel TES arrays? |
| Questions |
|---|
| Are there ways EREXS could address the IXO science objectives not discussed in the RFI response? |
| Please comment on source confusion / identification issues for the AGN survey. |
| Clarify how SXI data requirements for science are mitigated since this instrument is not present (but still referenced). |
| How are BH masses determined from HXI and IRT data in tidal disruption events and what observing cadence is required? |
| Questions |
|---|
| “When did SMBH grow?” is a main science topic, and up to 90% of the hard x-ray background could be resolved with HEX-P. However, there are uncertainties in the models, pending NuSTAR results. How large are these uncertainties? |
| How will source confusion affect the number of sources detected in the deep 1x1 degree survey? |
| Can you add more details on the cluster science? It is unclear what will really be measured. |
| How is your science affected if the mirrors can only achieve 30” angular resolution? |
| Please clarify the time resolution and physical size of the soft-band detectors. The response says that eRosita detectors will be used. We understand these to be pn CCDs, which on eRosita will provide 50msec time resolution. Is it required that these detectors provide 0.1 msec time resolution for HEX-P, and if so, can they do so? If not, will some technology development be required in this area? |
| The RFI response indicates that MPE Si detectors will be used, but there are no MPE people listed on the document. Has MPE has been consulted about providing the detectors, or are those detectors are just intended to be a strawman selection? |
| Questions |
|---|
| Can SAHARA address “What happens close to a black hole” using Fe-L line measurements? |
| What is the actual energy range of the mission? A range of 0.2-3 keV is stated, but then there is some discussion of the Fe K lines, and the effective area curve shows significant area there. But there are statements that the 6-7 keV range isn’t required. Is there some limitation of the instrument design that precludes using those photons? |
| Unlike the Fe K lines, the Fe L lines form a complex of many closely spaced lines, some of which are also close in energy to Ne lines. Please explain how the expected velocity shifts due to strong gravity effects compare to the line spacing, and demonstrate that line confusion will not make the use of Fe L lines for this purpose impractical. Will you need the K line measurements as well as L lines to decipher what is going on? |
| For the SMBH growth SAHARA will not measure black hole spin, but will search for and measure AGN winds in ~ 500 serendipitous sources / year. How will this measurement answer the question of how supermassive black holes grow and how does it compare to spin measurements? |
| Please clarify what velocities are expected in AGN outflows and what the requirement is for resolving velocity structure (in km/s). |
| Please clarify what turbulent velocities are expected in the clusters and what the requirement is for resolving velocity structure (in km/s). Is the energy resolution in the outer regions of the calorimeter array (4 eV) adequate? |
| In the large-scale structure question there is no mention of WHIM measurements. Is this because the spectral resolution is not adequate? |
| For measuring the metallicity and velocity (connection between SMBH formation and large scale structure) how important are the FeK lines? (SAHARA has very little effective area above 2 keV.) |
| Please show a histogram of energy resolution from existing arrays of TES (with and without hydra design). |
| Questions |
|---|
| Tell us more about high rate science capabilities. Page 6 says “except for 1e6 c/s,” but the description of the APSI on page 5 mentions windowing and us timing. |
| Questions |
|---|
| Can more information on the science case be provided? In particular, how do these missions address IXO science objectives? |
| How does the polarimeter work? |
| Can you compare these technologies to those of currently operating missions, and missions soon to be launched and under study? |
| Can black hole tracker at 2000kg really be made for $200m? |
| Questions |
|---|
| Can more information be provided about how WFXIS addresses IXO science objectives? |
| Does a mirror design for 10” over large FOV now exist, with ROSAT style mirrors? |
| Are 500x500 readouts for the calorimeter feasible? |
| Questions |
|---|
| Can WFXT address “What happens close to a black hole” using Fe-L line measurements? |
| For how many AGN in the survey will WFXT be able to directly measure masses and spins from the X-ray spectrum? |
| How will the 1200-9000 z>6 AGN be identified? By WFXT itself from Fe K lines, or in followup surveys? If the space density of z>6 AGN is uncertain by a factor of >20, how can the expected number of AGN be limited to a range of < 10x? |
| How many clusters, at which redshifts, will WFXT be able to measure as mass proxies? |
| Regarding cluster cosmology, what will be the advance of WFXT over eROSITA, especially in regards to the DE measurements (e.g. Figure 5)? |
| Questions |
|---|
| Are there ways WHIMEx could address the IXO science objectives not discussed in the RFI response? |
| Can WHIMEx address “What happens close to a black hole” using Fe-L line measurements? |
| How well will observations of 26 AGN (at what redshifts?) constrain the properties of the WHIM? How do these constraints complement or extent the results from the Lyman alpha forest studies (e.g. Lidz et al 2010 MNRAS 406, L25) and the future results expected from BOSS? |
| What will detection of mass outflows in the relatively small AGN samples tell us (e.g. how well will these constrain models of AGN or their evolution (how do black holes grow?), or enrichment of the surrounding medium)? |
| Can WHIMEx measure continuum well enough to get line strengths for warm absorbers (i.e., at the Fe L shell)? |
| What fraction of the IXO science for WHIM and SMBH/LSS connection can WHIMEx do, for example based on the baseline IXO observing plan? |
| How was the $200M cost derived? Can a more detailed breakdown be provided? |
| Questions |
|---|
| Are there ways Xenia could address the IXO science objectives not discussed in the RFI response? |
| Can additional information be provided about the plan to “map temperatures, masses and abundances of clusters beyond the virial radius”? (If results of some simulations were presented at the Workshop it would be very useful.) |
| Explain how the combination of the CRIS and HARI instruments might provide data that are much better than we can currently acquire with XMM (aside from the obvious exception of the calorimeter's spectral resolution). The RFI response states that both will have low background primarily due to the satellite being in low Earth orbit. Both CRIS and HARI have relatively low effective areas. CRIS has a rather large PSF of 4/2.5 arcmin HPD requirement/goal that will hinder any mapping effort. HARI would appear to be the preferred instrument for mapping, but it has CCD-like spectral resolution with less effective area than XMM. It is hard to see how these instruments can do better, especially for high Z clusters. Detailed simulations could support the argument. |
| Very little is said about the optics for the HARI instrument. The RFI response says that they use polynominal approximations to a Wolter I to reduce off-axis aberrations and provide excellent imaging performance over a wide field of view. It would be useful to see more details on the design of these optics. Are there prototypes that demonstrate this off-axis performance? |